Something else to consider: there are some key factors that determine how much energy yeast and bacteria can generate: temperature, hydration, salinity, pH, food supply and metabolic pathway (aerobic or anaerobic). In the case of a young dough, generally speaking, food supply is always high and oxygen is always low, so the others are the ones we need to be concerned with.

There are three main functions for which yeast and bacteria use energy, homeostasis (the basic cellular processes to maintain a stable environment inside the cell – i.e. life), growth, and division. There is a hierarchy as to how energy is spent; first is homeostasis, and only if there is energy left over, is there growth, and only if there is still energy left over, is there division. As the external environment becomes less ideal (temp too high or low, pH too high or low, salinity too high, food too low, etc.) , the less efficient the cell becomes and the more energy must be devoted to homeostasis – simply staying alive – leaving less for growth and reproduction.

Extended periods of cold hit the yeast two ways – lower temp and lower pH. Both require the cell to devote more and more energy to homeostasis. 100% of the energy the cell has available comes from carbohydrate metabolism, and as previously discussed, this creates CO2. If you see signs of CO2 being produced, you have energy production. This does not mean you have significant division however, and if you’re not seeing much in the way of bubbles in the fridge, it’s not very likely that you have any meaningful division.

I bring this up because even if you’re right about weaker cells dying off, you probably don’t have reason to believe they are being replaced by stronger cells.

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"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza." Craig's Neapolitan Garage

Something else to consider: there are some key factors that determine how much energy yeast and bacteria can generate: temperature, hydration, salinity, pH, food supply and metabolic pathway (aerobic or anaerobic). In the case of a young dough, generally speaking, food supply is always high and oxygen is always low, so the others are the ones we need to be concerned with.

There are three main functions for which yeast and bacteria use energy, homeostasis (the basic cellular processes to maintain a stable environment inside the cell – i.e. life), growth, and division. There is a hierarchy as to how energy is spent; first is homeostasis, and only if there is energy left over, is there growth, and only if there is still energy left over, is there division. As the external environment becomes less ideal (temp too high or low, pH too high or low, salinity too high, food too low, etc.) , the less efficient the cell becomes and the more energy must be devoted to homeostasis – simply staying alive – leaving less for growth and reproduction.

Extended periods of cold hit the yeast two ways – lower temp and lower pH. Both require the cell to devote more and more energy to homeostasis. 100% of the energy the cell has available comes from carbohydrate metabolism, and as previously discussed, this creates CO2. If you see signs of CO2 being produced, you have energy production. This does not mean you have significant division however, and if you’re not seeing much in the way of bubbles in the fridge, it’s not very likely that you have any meaningful division.

I bring this up because even if you’re right about weaker cells dying off, you probably don’t have reason to believe they are being replaced by stronger cells.

This is very nice information, thank you for sharing.

I understand your explanation completely, and I agree about your conclusion. I just want to share my train of thought so you understand how my brain processes this new info.

Assume 100 people are left out in a winter desert overnight with nothing but a t-shirt and shorts. Just like your yeast survival hierarchy, there is certainly a hierarchy of survival for a human being. An important note would be that every human will react to an outside environment differently. Therefore (for example) of the 100 people, 22 will die, 48 will have hypothermia and lose limbs, and the remaining 30 will survive with no major injuries.

Do yeast have the same variations in survival? I don't know. If they do it would be to a much lesser extent than humans since they are "simple" organisms.

One more thought would be that the yeast on the outside of the dougball would be subjected to lower temperatures than the inside the center of the doughball. Perhaps my "weaker" yeast are simply the yeast within 1" of the outer layer of the doughball.

I understand this is an unusual experiment with no added benefit for "big picture" pizza making. It's just something I started that I'd like to continue. I'm going to use your suggestion on my next experiment and make 1 large batch of pizza dough, divide and scale into 3 separate doughballs, then make them at 3 different times over 2-3 weeks.

I already made the 12.75% last night so I'll finish that experiment first.

Assume 100 people are left out in a winter desert overnight with nothing but a t-shirt and shorts. Just like your yeast survival hierarchy, there is certainly a hierarchy of survival for a human being. An important note would be that every human will react to an outside environment differently. Therefore (for example) of the 100 people, 22 will die, 48 will have hypothermia and lose limbs, and the remaining 30 will survive with no major injuries.

Do yeast have the same variations in survival? I don't know. If they do it would be to a much lesser extent than humans since they are "simple" organisms.

This is where i was going when I asked "by 'weak' do you mean genetically less fit, or simply old and tired?

There are always going to be older cells that will die more quickly when stress increases, but you are talking about the other case - natural selection - survival of the fittest. Your are suggesting that there are cells with a greater ability to maintain homeostasis in colder conditions and the offspring of these cells will share that ability. You are also suggesting that the difference between the two types of cells (those that can and those that can't) is so stark that you will see a difference in only one dough-making cycle. I tend to doubt this is the case, however uf you are right, and if you were to grow a new SD culture out of the old dough and repeat the cycle a couple times, you should have a strain of SD that is super cold resistant.

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"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza." Craig's Neapolitan Garage

This is where i was going when I asked "by 'weak' do you mean genetically less fit, or simply old and tired?

There are always going to be older cells that will die more quickly when stress increases, but you are talking about the other case - natural selection - survival of the fittest. Your are suggesting that there are cells with a greater ability to maintain homeostasis in colder conditions and the offspring of these cells will share that ability. You are also suggesting that the difference between the two types of cells (those that can and those that can't) is so stark that you will see a difference in only one dough-making cycle. I tend to doubt this is the case, however uf you are right, and if you were to grow a new SD culture out of the old dough and repeat the cycle a couple times, you should have a strain of SD that is super cold resistant.

That's an interesting twist to my assumptions. An evolution of yeast, so to speak. This wasn't the intent of my experimentations but sounds like an interesting side-experiment. You would assume a starter that is "put to sleep" in the refrigerator (such as mine) would start to take on these attributes though. It's also the assumption that the offspring of cells actually maintain the parent cell attributes as you mentioned. I'm no microbiology expert, so I cannot comment on this claim.

Anyhow, a successful experiment of a single dough-making cycle is certainly not a reason to contact Popular Science magazine, however if the entire "cycle" is repeated many times and shows similar results, I'd start questioning the validity of my assumptions.

You would assume a starter that is "put to sleep" in the refrigerator (such as mine) would start to take on these attributes though. It's also the assumption that the offspring of cells actually maintain the parent cell attributes as you mentioned. I'm no microbiology expert, so I cannot comment on this claim.

I would not make that assumption. What would be the basis? Excluding the presence of a mutagen, it is a good assumption that the offspring of cell division are genetically identical to the parent. These cultures, such as Ischia, have been around for a long time. Weaker strains should have died off long ago. This is why they generally don't change over time the way cultures you capture locally tend to change as they mature. Why would you assume that all the yeast in your culture are not substantually similar having decended from the strongest yeast? Maybe they are not, but I don't see a basis for that assumption off the bat.

If you're going to be scientific, your null hypothesis would be that there is not enough difference in the cells for the yeast to naturally select into a meaningfully more cold-resistant culture. It's not enough to get a result that suggests your alternate hypothesis (that the yeast culture will become more cold tolerant after exposure to colder temps) is correct. You must disprove the null hypothesis which is much more difficult.

My doubt lies in the idea that the difference is so stark between the less and more cold-tolerant cells that you will see a difference - let alone in one cycle.

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"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza." Craig's Neapolitan Garage

I would not make that assumption. What would be the basis? Excluding the presence of a mutagen, it is a good assumption that the offspring of cell division are genetically identical to the parent. These cultures, such as Ischia, have been around for a long time. Weaker strains should have died off long ago. This is why they generally don't change over time the way cultures you capture locally tend to change as they mature. Why would you assume that all the yeast in your culture are not substantually similar having decended from the strongest yeast? Maybe they are not, but I don't see a basis for that assumption off the bat.

If you're going to be scientific, your null hypothesis would be that there is not enough difference in the cells for the yeast to naturally select into a meaningfully more cold-resistant culture. It's not enough to get a result that suggests your alternate hypothesis (that the yeast culture will become more cold tolerant after exposure to colder temps) is correct. You must disprove the null hypothesis which is much more difficult.

My doubt lies in the idea that the difference is so stark between the less and more cold-tolerant cells that you will see a difference - let alone in one cycle.

Without completely de-railing this discussion, I would agree with you that all yeast cells would be 99.9% identical. But that 0.1% remaining would be the basis of evolution as we know it. While the yeast are probably 99% similar now as it was 500 years ago, I might argue that due to the process of evolution they have actually changed since then. This evolution is probably undetectable by us, but wouldn't mean it didn't happen.

Back to the topic on hand: This discussion does compliment your argument that the difference between cells would not be enough to see a difference in the big picture. To that I give you a point.

How about the argument of external yeast vs. internal yeast? Seems a much easier pill to swallow.

Without completely de-railing this discussion, I would agree with you that all yeast cells would be 99.9% identical. But that 0.1% remaining would be the basis of evolution as we know it. While the yeast are probably 99% similar now as it was 500 years ago, I might argue that due to the process of evolution they have actually changed since then. This evolution is probably undetectable by us, but wouldn't mean it didn't happen.

Back to the topic on hand: This discussion does compliment your argument that the difference between cells would not be enough to see a difference in the big picture. To that I give you a point.

How about the argument of external yeast vs. internal yeast? Seems a much easier pill to swallow.

It would probably be a case of adaptation not evolution. And maybe you're right about 0.1%, notwithstanding it seems highly unlikely that 14 days in the fridge could develop that that level of difference to something you can quantify with casual observation vs. 5 days in the fridge or 1 day in the fridge.

I'm not sure what you mean by external yeast vs. internal yeast?

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"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza." Craig's Neapolitan Garage

notwithstanding it seems highly unlikely that 14 days in the fridge could develop that that level of difference to something you can quantify with casual observation vs. 5 days in the fridge or 1 day in the fridge.

One more thought would be that the yeast on the outside of the dougball would be subjected to lower temperatures than the inside the center of the doughball. Perhaps my "weaker" yeast are simply the yeast within 1" of the outer layer of the doughball.

You might stick an instant read thermometer in one and see how long it takes the ball to equalize at the refrigerator temperature. I can't imaging it takes very long - certainly not compared to 5 or 14 days.

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"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza." Craig's Neapolitan Garage

You might stick an instant read thermometer in one and see how long it takes the ball to equalize at the refrigerator temperature. I can't imaging it takes very long - certainly not compared to 5 or 14 days.

The idea was that (similar to mass effect) the center of the doughball would be slightly warmer than the exterior due to activity of the yeast, and therefore never equalize.

The idea was that (similar to mass effect) the center of the doughball would be slightly warmer than the exterior due to activity of the yeast, and therefore never equalize.

I say no chance the difference is meaningful. You've already told me that there is almost zero activity in the fridge. I doubt if it is >0.1F. Maybe if you have 40kg of dough in bulk at room temp, but not one ball in the fridge. I stand to be corrected if measurements prove me wrong.

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"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza." Craig's Neapolitan Garage

Well it looks like I solved the mystery of why the results from experiment #4 were out of place.

I took a digital probe thermometer to the dough to test the difference in temperature between the exterior & center of the dough. My dough temp was a blistering 31*F. I put this dough (as well as experiment #4 dough) in the lowest drawer of my fridge.

I took a temp of food sitting on the middle shelf where my previous experiments were and got 36*F. Top shelf foods were 40*F. Amazing the temperature difference. I imagine the yeast in Dough #4 was in fact "damaged" from below freezing temps.

Still going to continue my original experiment and stay on the original middle shelf (36*) from now on.

24 hours in fridge, re-balled than 24 hours at 65*. I made the dough using GM Better for bread flour. I did an identical dough tonight but used ADY & All-trumps bromated. The results were only slightly different, where flavor was in favor of the Ischia dough, and color/dough strength in favor of the all trumps dough. Never had much luck with top crust color, but flavor completely over-shadows that flaw. Camera also isn't the best quality so crust looks more pale than it actually was.

24 hours in fridge, re-balled than 24 hours at 65*. I made the dough using GM Better for bread flour. I did an identical dough tonight but used ADY & All-trumps bromated. The results were only slightly different, where flavor was in favor of the Ischia dough, and color/dough strength in favor of the all trumps dough. Never had much luck with top crust color, but flavor completely over-shadows that flaw. Camera also isn't the best quality so crust looks more pale than it actually was.

Edit: Added picture of reheated slice in better light

I believe that due to the re-balling, especially in the lack of presence of sugar, you will most likely always have a lack of top color. However, there are a couple of other factors you may want to consider..1. Position of your stone in the oven (assuming you're using a home oven), a higher position would help with the top browning especially in an electric oven with a top element. You may also want to include some broiler time during the bake, that will also help.2. For the amount of starter and basically a 48 hour ferment, I dont think there is going to be enough residual sugars left within the dough to provide the color you desire. Especially with the re-balling and lack of added sugar to your dough.

There are always a miriad of factors at play with any dough.. I hope if you consider employing these into your regimine that they work out for you. All things considered, practice (and experimentation) make perfect. You're well on your way.

You may want to have a look at member Glutenboy, I believe he employs a long ferment as well as a re-ball and has had good results. Seems along the lines of what you're doing.

I had something come up right before I was about to bake this weekend, so I had to put everything on hold until later.

64% hydration, 3% active starter. 20 hr bulk room temp fermentation (~72°). Balled about 3 hours RT then put the whole flat into the fridge until I could come back to bake about 5 hours later. Normally, these dough balls would have been completely blown out and over fermented by the time I got to them if I left them at RT. The fridge slowed them down perfectly, the balls didn't merge together in the dough tray. I let them warm up for about a half hour at 70° while my LBE warmed up. When I stretched them, they were still a little cold and tricky to open up. Not a deal breaker, but took some getting used to on the first couple. After shaping they had the tell tale signs of little dough air bubbles all over the skins. These were some of the best tasting and best oven spring pies I've made in a while. I was skeptical of the fridge retarding, but it worked great. Granted, it was a short-ish retarding, but it worked great and extended my service window. No pics as I was baking in the middle of the night, but they were great.

I've since stopped using Ischia for my NY pies, but I think I recall going 2 weeks in the fridge with still very good results. The only issue at 2 weeks was poor dough strength, which just meant I had to be much more careful when opening a skin.

Does this produce an optimal pie? Probably not. But if your schedule changes, no need to toss the dough (pun intended)

I had something come up right before I was about to bake this weekend, so I had to put everything on hold until later.

64% hydration, 3% active starter. 20 hr bulk room temp fermentation (~72°). Balled about 3 hours RT then put the whole flat into the fridge until I could come back to bake about 5 hours later. Normally, these dough balls would have been completely blown out and over fermented by the time I got to them if I left them at RT. The fridge slowed them down perfectly, the balls didn't merge together in the dough tray. I let them warm up for about a half hour at 70° while my LBE warmed up. When I stretched them, they were still a little cold and tricky to open up. Not a deal breaker, but took some getting used to on the first couple. After shaping they had the tell tale signs of little dough air bubbles all over the skins. These were some of the best tasting and best oven spring pies I've made in a while. I was skeptical of the fridge retarding, but it worked great. Granted, it was a short-ish retarding, but it worked great and extended my service window. No pics as I was baking in the middle of the night, but they were great.

I've since stopped using Ischia for my NY pies, but I think I recall going 2 weeks in the fridge with still very good results. The only issue at 2 weeks was poor dough strength, which just meant I had to be much more careful when opening a skin.

Does this produce an optimal pie? Probably not. But if your schedule changes, no need to toss the dough (pun intended)

JD,

What is your protocol now for your new york pies if you're no longer using ischia?

Cold ferment in fridge 2-3 days, simple punch down every 24 hours or as needed, and a tight reball 24 hours before bake. 3 day fridge ferment is my preferred timeframe, but 2 is good, 1 is a bit early.

This past weekend I made a simple NY cheese pie (amongst 6 others), and my guests claimed it was way better than anything local. Of course, they're not from NY so they are probably not the best judges. I am from NY though, and I couldn't be happier with my efforts after a few years of experimenting.